Unit blows cool for a little while and then the air stops blowing but the unit is still running.?

I suppose when you say " the air stops blowing but the unit is still running" you mean the air that is blowing is not cool. If so, then the thermostat is faulty or needs to be set a lower temperature setting. If the unit blows cool for a few minutes and not cool for a few minutes, then cool again, etc. (called short-cycling), the unit is low on freon.